The TCP/IP stack

What is the 4 TCP/IP stack layers?

• Application

• Transport

• Network

• Link

What is the purpose of the application layer?

• Selects the correct protocol

• Interacts with the users application

What is the purpose of the transport layer?

• Establishes a virtual path

• Splits the transmission into packets

What is a virtual path?

An end to end encrypted connection between the sender and receiver

What is added to the packets at the transport layer

• Sequence number

• Port number

What does the port number identify?

The protocol in use

What is the purpose of the network layer?

Provides the correct IP addresses for the source and destination on the packet

What layer of the TCP/IP stack do routers work in?

Network layer

What is the purpose of the link layer?

• Controls the physical connections and hardware of the transmission

What is added in link layer and what’s the purpose?

MAC addresses are added which signify the next piece of hardware the packet needs to be sent to

When the packet is received what occurs?

The TCP/IP stack in reverse. All data is removed from the packet that was added

Once the packet is stripped of excess information, what occurs?

• The port number is used to decide what application for the data to be sent to

• The sequence number is used to order the packets

What does the application layer do on the receiving end?

Displays the data on the application

What is a socket address?

An ip address followed by a colon and then the port number

What does a socket number do?

Identifies what applications the data needs to be sent to on the recipient device

What is the purpose of FTP?

Allows users to transfer files via connecting to an FTP server and requesting the files

What is the purpose of HTTP?

Allows web servers to transfer text to users

What is the difference between HTTP and HTTPS

HTTPS is encrypted

What does POP3 do?

Allows users to download emails from an email server

What is the purpose of SMTP?

Allows users to send emails from an email server

What is the purpose of SSH?

It allows computers to be controlled remotely.

What is an SSH client?

Software that can be used to make a remote TCP connection so commands can be sent